Re: [LKP] [sched/numa] a43455a1d57: +94.1% proc-vmstat.numa_hint_faults_local

From: Rik van Riel
Date: Tue Aug 05 2014 - 17:43:49 EST


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On 07/31/2014 01:04 AM, Aaron Lu wrote:

>>>> +++ b/kernel/sched/fair.c @@ -924,10 +924,12 @@ static inline
>>>> unsigned long group_faults_cpu(struct numa_group *group, int
>>>> nid)
>>>>
>>>> /* * These return the fraction of accesses done by a
>>>> particular task, or - * task group, on a particular numa
>>>> node. The group weight is given a - * larger multiplier, in
>>>> order to group tasks together that are almost - * evenly
>>>> spread out between numa nodes. + * task group, on a
>>>> particular numa node. The NUMA move threshold + * prevents
>>>> task moves with marginal improvement, and is set to 5%. */
>>>> +#define NUMA_SCALE 1024 +#define NUMA_MOVE_THRESH (5 *
>>>> NUMA_SCALE / 100)
>>
>> It would be good to see if changing NUMA_MOVE_THRESH to
>> (NUMA_SCALE / 8) does the trick.
>
> With your 2nd patch and the above change, the result is:

Peter,

the threshold does not seem to make a difference for the
performance tests on my system, I guess you can drop this
patch :)

- --
All rights reversed
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